Relating the biological stability of soil organic matter to energy availability in deep tropical soil profiles

Stone, Madeleine M.; Plante, Alain F.

doi:10.1016/j.soilbio.2015.07.008

Cited by 39 publications

(14 citation statements)

References 61 publications

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“…), suggests that thermal stability may play an important role in C stabilization in the soil. Other studies have also suggested that thermal analysis may serve as a proxy for biogeochemical stability (Siewert et al ., ; Stone & Plante, ). The finding of our study shows how the greater stabilization of SOM resulting from both litter composition and a higher incidence of wildfires would contribute to C sink strength in the soils of drier sites.…”

Section: Discussionmentioning

confidence: 97%

Variations in soil carbon sequestration and their determinants along a precipitation gradient in seasonally dry tropical forest ecosystems

Campo

Merino

2016

Global Change Biology

107

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The effect of precipitation regime on the C cycle of tropical forests is poorly understood, despite the existence of models that suggest a drier climate may substantially alter the source-sink function of these ecosystems. Along a precipitation regime gradient containing 12 mature seasonally dry tropical forests growing under otherwise similar conditions (similar annual temperature, rainfall seasonality, and geological substrate), we analyzed the influence of variation in annual precipitation (1240 to 642 mm) and duration of seasonal drought on soil C. We investigated litterfall, decomposition in the forest floor, and C storage in the mineral soil, and analyzed the dependence of these processes and pools on precipitation. Litterfall decreased slightly - about 10% - from stands with 1240 mm yr(-1) to those with 642 mm yr(-1), while the decomposition decreased by 56%. Reduced precipitation strongly affected C storage and basal respiration in the mineral soil. Higher soil C storage at the drier sites was also related to the higher chemical recalcitrance of litter (fine roots and forest floor) and the presence of charcoal across sites, suggesting an important indirect influence of climate on C sequestration. Basal respiration was controlled by the amount of recalcitrant organic matter in the mineral soil. We conclude that in these forest ecosystems, the long-term consequences of decreased precipitation would be an increase in organic layer and mineral soil C storage, mainly due to lower decomposition and higher chemical recalcitrance of organic matter, resulting from changes in litter composition and, likely also, wildfire patterns. This could turn these seasonally dry tropical forests into significant soil C sinks under the predicted longer drought periods if primary productivity is maintained.

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Section: Discussionmentioning

confidence: 97%

Variations in soil carbon sequestration and their determinants along a precipitation gradient in seasonally dry tropical forest ecosystems

Campo

Merino

2016

Global Change Biology

107

View full text Add to dashboard Cite

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“…A review of the literature suggests that the papers that focus specifically on mechanisms of destabilization largely emerge over the past decade (e.g. [6][7][8][9][10][11][12][13][14][15][16][17][18][19]), with a sharp increase in these sample publications in the past 3 years. It has become evident that the processes of C destabilization are not mere reversals of the processes of C stabilization.…”

Section: Introductionmentioning

confidence: 99%

What do we know about soil carbon destabilization?

Bailey

Pries

Lajtha

2019

Environ. Res. Lett.

144

106

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Most empirical and modeling research on soil carbon (C) dynamics has focused on those processes that control and promote C stabilization. However, we lack a strong, generalizable understanding of the mechanisms through which soil organic carbon (SOC) is destabilized in soils. Yet a clear understanding of C destabilization processes in soil is needed to quantify the feedbacks of the soil C cycle to the Earth system. Destabilization includes processes that occur along a spectrum through which SOC shifts from a ‘protected’ state to an ‘available’ state to microbial cells where it can be mineralized to gaseous forms or to soluble forms that are then lost from the soil system. These processes fall into three general categories: (1) release from physical occlusion through processes such as tillage, bioturbation, or freeze-thaw and wetting-drying cycles; (2) C desorption from soil solids and colloids; and (3) increased C metabolism. Many processes that stabilize soil C can also destabilize C, and C gain or loss depends on the balance between competing reactions. For example, earthworms may both destabilize C through aggregate destruction, but may also create new aggregates and redistribute C into mineral horizon. Similarly, mycorrhizae and roots form new soil C but may also destabilize old soil C through priming and promoting microbial mining; labile C inputs cause C stabilization through increased carbon use efficiency or may fuel priming. Changes to the soil environment that affect the solubility of minerals or change the relative surfaces charges of minerals can destabilize SOC, including increased pH or in the reductive dissolution of Fe-bearing minerals. By considering these different physical, chemical, and biological controls as processes that contribute to soil C destabilization, we can develop thoughtful new hypotheses about the persistence and vulnerability of C in soils and make more accurate and robust predictions of soil C cycling in a changing environment.

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“…As expected, SOC − CO 2 emissions were larger in the topsoil than in the subsoil. However, the SOC decomposition rates were similar in the topsoil and in the subsoil, suggesting that deep SOC is as prone to decomposition as surface SOC under optimal incubation conditions (Stone & Plante, 2015). This, therefore, suggests that the size of the decomposing carbon pool was smaller in the subsoil, but its potential decomposition rate was not reduced (Salomé et al, 2010).…”

Section: Contribution Of Sic-derived Co 2 To Total Emissionsmentioning

confidence: 89%

Organic carbon decomposition rates with depth and contribution of inorganic carbon to CO₂emissions under a Mediterranean agroforestry system

Cardinael

Chevallier

Guenet

et al. 2019

European J Soil Science

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Agroforestry systems have been much studied for their potential to store soil organic carbon (SOC). However, few data are available on their specific impact on potential SOC mineralization, especially at depth in subsoils. Moreover, many soils of the world, especially in arid and semiarid environments, also contain large stocks of soil inorganic carbon (SIC) as carbonates. Consequently, the organic carbon dynamics have been poorly investigated in these soils due to the complexity of measurements and of the processes involved. To assess mineralization rates of SOC with depth, we incubated soil samples from an 18‐year‐old agroforestry system (both tree row and alley) and an adjacent agricultural plot established on a calcareous soil in France. Soil samples were taken at four different depths: 0–10, 10–30, 70–100 and 160–180 cm. Total CO2 emissions, the isotopic composition (δ13C, ‰) of the CO2 and microbial biomass were measured. The SIC concentrations ranged from 48 to 63 g C kg−1 soil and the SOC concentrations ranged from 4 to 17 g C kg−1 soil. The contribution of SIC‐derived CO2 represented about 20% in the topsoil and 60% in the subsoil of the total soil CO2 emissions. The microbial biomass and the SOC‐derived CO2 emissions were larger in the topsoil, but the decomposition rates (day−1) remained stable with depth, suggesting that only the size of the labile carbon pool was modified with depth. Subsoil organic carbon seems to be as prone to decomposition as surface organic carbon. No difference in CO2 emissions was found between the agroforestry and the control plot, except in the tree row at 0–10 cm. Our results suggest that the measurement of soil respiration in calcareous soils could be overestimated if the isotopic signature of the CO2 is not taken into account. It also advocates more in‐depth studies on carbonate dissolution–precipitation processes and their impact on CO2 emissions. Highlights We measured SOC mineralization and inorganic carbon contribution to CO2 emissions in agroforestry Subsoil organic carbon was as prone to decomposition as surface organic carbon Inorganic carbon contribution to CO2 emissions ranged from 20 to 60% depending on soil depth Measurement of soil respiration in calcareous soils could be overestimated

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Relating the biological stability of soil organic matter to energy availability in deep tropical soil profiles

Cited by 39 publications

References 61 publications

Variations in soil carbon sequestration and their determinants along a precipitation gradient in seasonally dry tropical forest ecosystems

Variations in soil carbon sequestration and their determinants along a precipitation gradient in seasonally dry tropical forest ecosystems

What do we know about soil carbon destabilization?

Organic carbon decomposition rates with depth and contribution of inorganic carbon to CO₂emissions under a Mediterranean agroforestry system

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Relating the biological stability of soil organic matter to energy availability in deep tropical soil profiles

Cited by 39 publications

References 61 publications

Variations in soil carbon sequestration and their determinants along a precipitation gradient in seasonally dry tropical forest ecosystems

Variations in soil carbon sequestration and their determinants along a precipitation gradient in seasonally dry tropical forest ecosystems

What do we know about soil carbon destabilization?

Organic carbon decomposition rates with depth and contribution of inorganic carbon to CO2emissions under a Mediterranean agroforestry system

Contact Info

Product

Resources

About

Organic carbon decomposition rates with depth and contribution of inorganic carbon to CO₂emissions under a Mediterranean agroforestry system